University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Jan Bockholt
(2014):
RAINFALL PARTITIONING AND SOLUTE FLUXES IN A PURE BEECH STAND AND THE EFFECT OF DROUGHTS AND HEAVY RAIN EVENTS AT PLOT SCALE.
Master / Diploma Thesis - Institut für Bodenforschung (IBF),
BOKU-Universität für Bodenkultur,
pp 82.
UB BOKU
obvsg
- Abstract:
- Frequency and intensity of droughts and heavy rain events are predicted to increase because of climate change and might influence soil water dynamics and nutrient leaching in temperate forest ecosystems. We investigated nutrient leaching and water fluxes by means of a throughfall manipulation experiment in a pure beach stand (Fagus Sylvatica L.) for 6 months. By installing roofs and an irrigation system we applied two treatments of different rain and drought frequencies and intensities. Treatment 1 (T1) received 6 drought-stress cycles and treatment 2 (T2) received 3 drought-stress cycles. After each drought-stress cycle we irrigated the soil with 75 l m-2 (T1) and 150 l m-2 (T2), respectively. The determination of water fluxes and nutrient input to the control plot was assessed by throughfall (TF) and stemflow (SF) measurements. Litter percolate (LP) and soil water (SW) were measured biweekly. Additionally, the effect of drying and rewetting was simulated by using the soil water model HYDRUS-2D. TF, SF and interception accounted for 59.5%, 10.4% and 30.1% of total precipitation, respectively. Net rainfall enrichment was found for DOC, PO4-, SO42, NO3-N and NO2-N, whereas Cl-, TN and NH4-N showed depletion. Significant differences in nutrient concentration were found among LP, SW, TF, SF and bulk precipitation for the control plot but not for T1 and T2. Cumulative nutrient fluxes were found to decrease with longer droughts and higher rainfall intensities, whereas for single rain events an elevated nutrient translocation was found particular for NO3-N. Simulated water contents revealed best results for the control plot (RMSE 0.02 cm3 cm-3), whereas the goodness-of-fit between modeled and observed water content decreased for T1 (RMSE 0.03 cm3 cm-3) and T2 (RMSE 0.04 cm³ cm-3). We presume that drying and rewetting resulted in preferential flow and soil water repellency which could not be projected accurately by the soil water simulations.
- Beurteilende(r): Zechmeister-Boltenstern Sophie
- 1.Mitwirkender: Zimmermann Michael
- 2.Mitwirkender: Schwen Andreas